1. Field of the Invention
The present invention relates to ultrasonic surgical probes or ultrasonic cutting devices for use in the removal of tissue and/or matter from a living body, and more particularly, to an improved ultrasonic probe which is capable of removing tissue through activation or cavitation of a fluid by ultrasonic vibration, and in which the ultrasonically activated member contains minimal features which may cause weakened portions.
2. Description of Related Art
Probes or scalpels for the fragmentation and removal of materials, tissue and fluids from living beings are known to the art. For example, U.S. Pat. No. 2,227,727, issued Jan. 7, 1941 to Vincent Leggiardro, discloses an apparatus for fragmenting naturally formed stones, such as kidney stones, and the like, utilizing a high speed reciprocating rod which may have a blunt end, a sharp or chisel point, a cutting blade, or combination thereof, such as a cutting blade having a blunt end.
While the apparatus disclosed in U.S. Pat. No. 2,227,727 involved a two part housing, with the sonic transducer in one part and the reciprocating rod in another part, in later apparatus the transducer and probe were connected together to form a unitary instrument. In U.S. Pat. No. 3,896,811, issued Jul. 29, 1975 to Karl Storz, the transducer and rod-like are coupled and both enveloped by a jacket providing an air gap and preventing the sides of the probe from contacting the body except at its end. An improvement in such instruments is disclosed in U.S. Pat. No. 3,990,452, issued Nov. 9, 1976 to Edward J. Murry and Joseph F. Brumbach, which also reviews a number of articles relating to the development of ultrasonics in medicine and notes the incorporation of irrigation and aspiration with ultrasonics.
A particular arrangement in an ultrasonically vibrated surgical tool using an irrigation fluid and an anti-coagulant is disclosed in U.S. Pat. No. 4,493,694, issued Jan. 15, 1985, to David G. Wuchinich, utilizes a hollow tool having a suction passage and at least one pre-aspirating orifice in the wall of the tool, and a plastic sleeve concentrically spaced about the tool for admitting fluid from a supply into the space between the tool and passing substantially all of the fluid through the pre-aspirating orifice.
In the application of ultrasonics to liposuction, instruments of varying configurations recently have been proposed. In U.S. Pat. No. 5,236,414, issued Aug. 17, 1993 to Katsuya Takasu, a tubular body defining a suction passage has an opening in its front lower end, and an outer tube having a corresponding opening, by means of which fat tissue is crushed and/or emulsified due to the vibration of the front end of the tubular body and is then aspirated. In U.S. Pat. No. 5,514,086, issued May 7, 1996, to Parisi et al., an ultrasonically vibrated hollow probe has a port in its surface for aspiration and a tip substantially formed of plastic.
In the previously known probes, particularly for the fragmentation or emulsification and aspiration of fat tissue, the ultrasonically activated member or tool had one or more ports or openings, which have been found to be points of stress which limited the amount of ultrasonic power which could be applied thereto, or limited the amount of travel or excursion of the distal end of the probe. If the power limit of the probe were exceeded, the probe was in danger of cracking at the points of stress, particularly at the ports or suction openings. Thus, there is a need for an improved ultrasonic surgical probe configuration which reduces the stress on the probe at higher ultrasonic power levels and at higher excursion of the distal end of the probe.